UI enhancements in the home and about page

Made some UI enhancements in the Home and About Page: 

1) Added a button which says "Create an Unhangout".
2) Added a favicon.
3) Added a logo image. 
4) Modified the color scheme of the Home and the about page.
5) Removed the jumbotron background-image from the home and the about page.  
6) Added a profile thumbnail on the navbar.